I love the thesaurus, but I've been frustrated by the limited definitions available. Often, I end up going in circles. For example, the synonym for "boil" could be "hot," and then a similar word for hot could be "not cold". Okay, I'm exaggerating a bit, but you get the idea. Is there some way that I/we submit words and definitions that could be included in future updates of the thesaurus?

Merriam-Webster provides a free online dictionary, thesaurus, audio pronunciations ... Welcome to Merriam-Webster's Open Dictionary where you can submit and share ... Use the submit form to create an entry for a new word or sense. Your word—complete with definition, example sentence, and your name if you choose.

I know of no way to add words and definitions to the Nisus thesaurus, however given that Apple now supply a full dictionary and thesaurus (The Oxford American Writer's) with Mac OS X I never use the Nisus one anymore. I would expect that in due course they will simply hook NWE/NWP directly into the OS X thesaurus and drop their one as it's essentially redundant nowadays.